Drosophila CNS mitochondrial DNA dysfunction microarray
Ontology highlight
ABSTRACT:
ORGANISM(S): Drosophila melanogaster
SUBMITTER: Ariana Gatt
PROVIDER: E-GEOD-53509 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Mitochondrial DNA (mtDNA) encodes essential components of the respiratory chain and loss of mtDNA leads to mitochondrial dysfunction and neurodegeneration. Mitochondrial transcription factor A (TFAM) is an essential component of mtDNA replication and a regulator of mitochondrial copy number in cells. Studies have shown that TFAM knockdown leads to mitochondrial dysfunction and respiratory chain deficiencies. ATP synthase is Complex V of the mitochondrial respiratory chain. It is driven by a proton gradient between the intermembrane space and the mitochondrial matrix and generates the majority of cellular ATP. The knockdown of coupling factor 6 (Cf6), one of the components of the proton channel F0, causes dysfunction in the complex, leading to mitochondrial dysfunction and respiratory chain deficiencies. Using gene expression analysis, we aimed to investigate the effects of mtDNA dysfunction in the CNS at the molecular level.
2013-12-20 | GSE53509 | GEO
Project description:Mitochondria are vital in providing cellular energy via their oxidative phosphorylation system, which requires the coordinated expression of genes encoded by both the nuclear and mitochondrial genomes (mtDNA). Transcription of the circular mammalian mtDNA depends on a single mitochondrial RNA polymerase (POLRMT). Although the transcription initiation process is well understood, it remains highly controversial if POLRMT also serves as the primase for initiation of mtDNA replication. In the nucleus, the RNA polymerases needed for gene expression have no such role. Conditional knockout of Polrmt in heart results in severe mitochondrial dysfunction causing dilated cardiomyopathy in young mice. We further studied the molecular consequences of different expression levels of POLRMT and found that POLRMT is essential for primer synthesis to initiate mtDNA replication in vivo. Furthermore, transcription initiation for primer formation has priority over gene expression. Surprisingly, mitochondrial transcription factor A (TFAM) exists in an mtDNA-free pool in the Polrmt knockout mice. TFAM levels remain unchanged despite strong mtDNA depletion and TFAM is thus protected from degradation of the AAA+ Lon protease in absence of POLRMT. Lastly, mitochondrial transcription elongation factor (TEFM) can compensate for a partial depletion of POLRMT in heterozygous Polrmt knockout mice, indicating a direct regulatory role for this factor in transcription. In conclusion, we present here the first in vivo evidence that POLRMT has a key regulatory role in replication of mammalian mtDNA and is part of a mechanism that provides a switch between RNA primer formation for mtDNA replication and mtDNA expression. Isolated heart mitochondria from three control mice (L/L) and three Polrmt knockout mice (L/L, cre), aged 3-4 weeks, were sequenced and analyzed for differential expression.
2016-08-05 | E-GEOD-83368 | biostudies-arrayexpress
Project description:Bao XR, Ong SE, Goldberger O, Peng J, Sharma R, Thompson DA, Vafai SB, Cox A, Marutani E, Ichinose F, Goessling W, Regev A, Carr SA, Clish CB, Mootha VK. eLife 2016. Mitochondrial dysfunction is associated with a spectrum of human disorders, ranging from rare, inborn errors of metabolism to common, age-associated diseases such as neurodegeneration. How these lesions give rise to diverse pathology is not well understood, partly because their proximal consequences have not been well-studied in mammalian cells. Here we provide two lines of evidence that mitochondrial respiratory chain dysfunction leads to alterations in one-carbon metabolism pathways. First, using hypothesis-generating metabolic, proteomic, and transcriptional profiling, followed by confirmatory experiments, we report that mtDNA depletion leads to an ATF4-mediated increase in serine biosynthesis and transsulfuration. Second, we show that lesioning the respiratory chain impairs mitochondrial production of formate from serine, and that in some cells, respiratory chain inhibition leads to growth defects upon serine withdrawal that are rescuable with purine or formate supplementation. Our work underscores the connection between the respiratory chain and one-carbon metabolism with implications for understanding mitochondrial pathogenesis.
2016-06-02 | MSV000079791 | MassIVE
Project description:The dynamin-like GTPases Mitofusin 1 and 2 (Mfn1 and Mfn2) are essential for mitochondrial function, which has been principally attributed to their regulation of fission/fusion dynamics. Here, we report that Mfn1 and 2 are critical for glucose-stimulated insulin secretion (GSIS) primarily through control of mtDNA content. Whereas Mfn1 and Mfn2 individually were dispensable for glucose homeostasis, combined Mfn1/2 deletion in β-cells reduced mtDNA content, induced impaired mitochondrial morphology and networking fragmentation, and impaired decreased respiratory function, ultimately resulting in severe glucose intolerance. Importantly, gene dosage studies unexpectedly revealed that Mfn1/2 control of glucose homeostasis was dependent on maintenance of mtDNA content, rather than mitochondrial structure. Indeed, pharmacologic mitofusin agonists rescued islet mtDNA depletion due to mitofusin deficiency independent of changes on mitochondrial structure. Mfn1/2 maintain mtDNA content by regulating the expression of the crucial mitochondrial transcription factor Tfam, as Tfam overexpression ameliorated the reduction in mtDNA content and GSIS in Mfn1/2-deficient β-cells. Thus, the primary physiologic role of Mfn1 and 2 in β-cells is coupled to preservation of mtDNA content rather than mitochondrial architecture, and Mfn1 and 2 may be promising targets to overcome mitochondrial dysfunction and restore glucose control in diabetes.
2022-02-16 | GSE194204 | GEO
Project description:Understanding the mechanisms of the Warburg shift to aerobic glycolysis is central to defining the metabolic basis of cancer. Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is an aggressive cancer characterized by bi-allelic inactivation of the gene encoding the Krebs cycle enzyme fumarate hydratase, an early shift to aerobic glycolysis, and rapid metastasis. We observed of the mitochondrial in tumors from HLRCC patients. Biochemical and transcriptomics analyses revealed that respiratory chain dysfunction in the tumors was due to loss of expression of mitochondrial DNA (mtDNA)-encoded subunits of respiratory chain complexes, caused by a marked decrease in mtDNA content and increased mtDNA mutations. We demonstrated that accumulation of fumarate in HLRCC tumors inactivated the core factors responsible for replication and proofreading of mtDNA, leading to loss of expression of respiratory chain components, thereby promoting the shift to aerobic glycolysis and disease progression in this prototypic model of glucose-dependent human cancer.
2021-01-22 | GSE157256 | GEO
Project description:Mammalian mitochondrial DNA (mtDNA) is coated with mitochondrial transcription factor A (TFAM) and compacted into nucleoids. TFAM is not only the main component of mitochondrial nucleoids but its levels can also control mtDNA copy number. Here we show that the TFAM-to-mtDNA ratio is critical for maintaining normal mtDNA expression in different tissues of the mouse. BAC transgenic mice with a 1.5-fold increase in TFAM protein levels maintain a normal TFAM-to-mtDNA ratio in different tissues and as a consequence mitochondrial gene expression, nucleoid distribution and whole animal metabolism are all unaltered. In contrast, mice expressing TFAM from the CAG promoter in the ROSA26 locus have 4.5-fold increase of TFAM protein levels in heart and skeletal muscle and develop pathology leading to early postnatal lethality. The TFAM-to-mtDNA ratio varies widely between tissues in these mice and is very high in skeletal muscle where it causes strong repression of mtDNA expression and deficient oxidative phosphorylation (OXPHOS) despite normal mtDNA levels. In heart, mtDNA copy number is increased leading to a near normal TFAM-to-mtDNA ratio and maintained OXPHOS capacity. In the liver, mtDNA expression is maintained despite increased TFAM levels and normal mtDNA levels. Here, tissue-specific induction of the LONP1 protease and mitochondrial RNA polymerase (POLRMT) expression counteracts the silencing effect of high TFAM levels. We conclude that the TFAM-to-mtDNA ratio has an important role in maintaining mtDNA expression in vivo. TFAM acts as a general repressor of mtDNA expression and this effect can be counterbalance by tissue-specific expression of regulatory factors.
2021-08-18 | PXD023050 | Pride
Project description:The goal of this analysis was to utilize microarray profiling to identify basal alterations in gene expression in response to TFAM depletion and mtDNA stress. Mitochondrial DNA (mtDNA) is normally present at thousands of copies per cell and is packaged into several hundred higher-order structures termed nucleoids. The abundant mtDNA-binding protein, TFAM (transcription factor A,mitochondrial), regulates nucleoid architecture, abundance and segregation. Complete mtDNA depletion profoundly impairs oxidative phosphorylation, triggering calcium-dependent stress signalling and adaptive metabolic responses. However, the cellular responses to mtDNA instability, a physiologically relevant stress observed in many human diseases and ageing, remain poorly defined. Here we show that moderate mtDNA stress elicited by TFAM deficiency engages cytosolic antiviral signalling to enhance the expression of a subset of interferon-stimulated genes. Mechanistically, we find that aberrant mtDNA packaging promotes escape of mtDNA into the cytosol, where it engages the DNA sensor cGAS (also known as MB21D1) and promotes STING (also known as TMEM173)–IRF3-dependent signalling to elevate interferon-stimulated gene expression, potentiate type I interferon responses and confer broad viral resistance. Furthermore, we demonstrate that herpesviruses induce mtDNA stress, which enhances antiviral signalling and type I interferon responses during infection. Our results further demonstrate that mitochondria are central participants in innate immunity, identify mtDNA stress as a cell-intrinsic trigger of antiviral signaling and suggest that cellular monitoring of mtDNA homeostasis cooperates with canonical virus sensing mechanisms to fully engage antiviral innate immunity. Murine embryonic fibroblasts were isolated from wild-type or Tfam+/- E13.5 littermate embryos. RNA from passage-matched wild-type and Tfam+/- MEF lines was extracted in duplicate and hybridized onto Affymetrix microarrays. Four arrays were performed in total with two technical replicates per genotype.
2015-01-26 | E-GEOD-63767 | biostudies-arrayexpress
Project description:Mitochondria are vital in providing cellular energy via their oxidative phosphorylation system, which requires the coordinated expression of genes encoded by both the nuclear and mitochondrial genomes (mtDNA). Transcription of the circular mammalian mtDNA depends on a single mitochondrial RNA polymerase (POLRMT). Although the transcription initiation process is well understood, it remains highly controversial if POLRMT also serves as the primase for initiation of mtDNA replication. In the nucleus, the RNA polymerases needed for gene expression have no such role. Conditional knockout of Polrmt in heart results in severe mitochondrial dysfunction causing dilated cardiomyopathy in young mice. We further studied the molecular consequences of different expression levels of POLRMT and found that POLRMT is essential for primer synthesis to initiate mtDNA replication in vivo. Furthermore, transcription initiation for primer formation has priority over gene expression. Surprisingly, mitochondrial transcription factor A (TFAM) exists in an mtDNA-free pool in the Polrmt knockout mice. TFAM levels remain unchanged despite strong mtDNA depletion and TFAM is thus protected from degradation of the AAA+ Lon protease in absence of POLRMT. Lastly, mitochondrial transcription elongation factor (TEFM) can compensate for a partial depletion of POLRMT in heterozygous Polrmt knockout mice, indicating a direct regulatory role for this factor in transcription. In conclusion, we present here the first in vivo evidence that POLRMT has a key regulatory role in replication of mammalian mtDNA and is part of a mechanism that provides a switch between RNA primer formation for mtDNA replication and mtDNA expression.
2016-08-05 | GSE83368 | GEO
Project description:Mitochondrial dysfunction caused by mitochondrial (mtDNA) deletions have been associated with skeletal muscle atrophy and myofiber loss. However, whether such defects occurring in myofibers cause sarcopenia is unclear. Also, the contribution of mtDNA alterations in muscle stem cells (MuSCs) to sarcopenia remain to be investigated. We expressed a dominant-negative variant of the mitochondrial helicase, which induces mtDNA alterations, specifically in differentiated myofibers (K320Eskm mice) and MuSCs (K320Emsc mice), respectively, and investigated their impact on muscle structure and function by immunohistochemistry, analysis of mtDNA and respiratory chain content, muscle transcriptome and functional tests. K320Eskm mice at 24 months of age had higher levels of mtDNA deletions compared to controls in soleus (SOL, 0.07673 % vs 0.00015 %, p=0.0167), extensor digitorium longi (EDL, 0.0649 vs 0.000925, p= 0.0015) and gastrocnemius (GAS, 0.09353 vs 0.000425, p=0.0004). K320Eskm mice revealed a progressive increase in the proportion of cytochrome c oxidase deficient fibers (COX-) in cross sections, reaching a maximum of 3.03%, 4.36%, 13.58% and 17.08% in EDL, SOL, tibialis anterior (TA) and GAS, respectively. However, mice did not show accelerated loss of muscle mass, muscle strength or physical performance. Histological analyses revealed ragged red fibers but also stimulated regeneration, indicating activation of MuSCs. RNAseq demonstrated enhanced expression of genes associated with protein synthesis, but also degradation, as well as muscle fiber differentiation and cell proliferation. In contrast, 7 days after destruction by cardiotoxin, regenerating TA of K320Emsc mice showed 30% of COX- fibers. Notably, regenerated muscle showed dystrophic changes, increased fibrosis (2.5% vs 1.6%, p=0.0003), increased abundance of fat cells (2.76% vs 0.23%, p=0.0144) and reduced muscle mass (regenerated TA: 40.0mg vs 60.2mg, p=0.0171). In contrast to muscles from K320Eskm mice, freshly isolated MuSCs from aged K320Emsc mice were completely devoid of mtDNA alterations. However, after passaging, mtDNA copy number as well as respiratory chain subunits and p62 levels gradually decreased.Taken together, accumulation of large-scale mtDNA alterations in myofibers alone is not sufficient to cause sarcopenia. Expression of K320E is tolerated in quiescent MuSCs, but progressively leads to mtDNA and respiratory chain depletion upon activation, in vivo and in vitro, possibly caused by an increased mitochondrial removal. Altogether, our results suggest that the accumulation of mtDNA alterations in myofibers activates regeneration during aging, which leads to sarcopenia if such alterations have expanded in MuSCs as well.
2022-03-26 | GSE199201 | GEO
Project description:Objective: To study if diabetic and insulin-resistant states lead to mitochondrial dysfunction in the liver, or alternatively, if there is adaption of mitochondrial function to these states in the long-term range. Results: High-fat diet (HFD) caused insulin resistance and severe hepatic lipid accumulation, but respiratory chain parameters were unchanged. Livers from insulin-resistant IR/IRS-1+/- mice had normal lipid contents and normal respiratory chain parameters, however showed mitochondrial uncoupling. Livers from severely hyperglycemic and hypoinsulimic, streptozotocin (STZ)-treated mice had massively depleted lipid levels, but respiratory chain abundance was unchanged. However, their mitochondria showed increased abundance and activity of the respiratory chain, which was better coupled compared to controls. Conclusions: Insulin resistance, either induced by obesity or by genetic manipulation, does not cause mitochondrial dysfunction in the liver of mice. However, severe insulin deficiency and high blood glucose levels in mice cause an enhanced performance of the respiratory chain, probably in order to maintain the high energy requirement of the unsuppressed gluconeogenesis. We performed gene expression microarray analysis on liver tissue derived from mice treated with STZ or standard diet (control).
2013-12-10 | E-GEOD-39752 | biostudies-arrayexpress